Conventionally, an inkjet printer described in Patent Document 1 is known. This inkjet printer includes a holder that relatively moves in a main scanning direction perpendicularly intersecting a printing direction with respect to a medium that is a print target, an ink head provided on the holder, and a first ultraviolet lamp and a second ultraviolet lamp provided on both right and left sides of the holder in the main scanning direction. The first ultraviolet lamp and the second ultraviolet lamp can move in a sub scanning direction (the direction perpendicularly intersecting the main scanning direction). The first ultraviolet lamp and the second ultraviolet lamp are driven by a motor. The motor is provided at a part of the holder. A rotation shaft of the motor projects from one end side of a side surface of the holder, and a pulley is provided on the rotation shaft.
Further, a rotation shaft also projects to the other end side of the side surface of the holder and a pulley is also provided at a tip of this rotation shaft. A drive belt is bridged over the pulleys. Further, the other end of the rotation shaft is projected to a side surface of the holder on the opposite side, and a pulley is also provided on this other end. Moreover, a rotation shaft is independently provided at a position coaxial to the rotation shaft of the motor, and this rotation shaft also projects from the side surface of the holder, and a pulley is provided thereon. A drive belt is similarly bridged over these pulleys as well.
Further, a guide rail is provided in the sub scanning direction on a lower side of a side surface of the holder. The first ultraviolet lamp and the second ultraviolet lamp are movably arranged on the guide rails. Further, upper portions of the first ultraviolet lamp and the second ultraviolet lamp are attached to the drive belts.
In this inkjet printer, the first ultraviolet lamp and the second ultraviolet lamp are moved forward (printing direction of the medium) by driving the motor, and offsets an effective irradiation region from a printing region in the sub scanning direction. Ultraviolet curing type ink injected from the ink head while moving in the main scanning direction adheres to the printing region in a recording paper. The adhered ink has its effective irradiation region offset in the sub scanning direction even when the holder moves in the main scanning direction, so the ink that has adhered to the recording paper is not completely irradiated with the ultraviolet ray, whereby the ink is not cured.
Next, in an in-bound of the holder in the main scanning direction, the recording paper is in a state of having been moved by an amount corresponding to the printing region, so the print region of the ink injected in this in-bound enters into the effective irradiation region, the ink is irradiated with the ultraviolet ray, and the ink is cured. As above, by injecting the ink in an out-bound and ultraviolet-irradiating in the in-bound, ultraviolet irradiation is performed for curing after a certain time has elapsed from the ink injection, so the ink is spread on the medium and a surface thereof becomes flat, and as a whole, glossy printing can be obtained.
On the other hand, by driving the first ultraviolet lamp and the second ultraviolet lamp by the motor and causing the printing region and the effective irradiation region to match in the sub scanning direction, ultraviolet irradiation can be performed onto the ink right after printing. Due to this, curing takes place before the injected ink is spread, so the surface becomes granular and matted.